Press brake



April 17, 1962 L. HARPER 3,029,858

PRESS BRAKE Filed Sept. 17, 1959 2 Sheets-Sheet 1 N \l I (71 IN V EN TOR.

LAFF/E HARPER BY ATTORNEYS United States Patent Ofifice 3,029,858 RESS BRAKE Lathe Harper, San Bruno, Calih, assignor to The Foundry Equipment 30., Cleveland, @hio Filed Sept. 17, 1959, Ser. No. 840,585 4 (Jlaims. (6i. 153-41) This invention relates to a press brake for use in forming bends in metal sheets. In the conventional press brake, there is a frame mounting a press ram for vertical reciprocable movement, which ram is adapted to carry the punch. Below the ram is a bolster plate to which the lower, or female, die is releasably secured.

These punches and dies, for the type of work done by the present invention, are horizontally elongated and they may be many feet in length.

The bolster plate is usually formed with an upwardly opening groove in which a rib on the lower die may t and be secured.

In many types of work, ditferent bends are made or formed in the same sheets, and in any event, the press brake must be adapted to make many difierent multiple bends.

Heretofore, the making of a different bend from the type previously made involves a time consuming operation and the separate dies are expensive and require space for storage when not in use.

One of the objects of the present invention is the provision of structure enabling the changing of one die form to another in a matter of seconds, and the reduction of the space heretofore required for storage of separate dies by reducing the number of separate dies for doing the same work heretofore needed.

In the present invention, a plurality of different die shapes are incorporated into a' single unit that is rotatable to dilferent positions, and which unit, while rotatable, is firmly bedded so that once the die is positioned properly for one form it will remain in correct and proper position for all of the forms incorporated therein after the die is rotated.

Other objects and advantages will appear in the description and in the drawings.

' In the drawings:

FIG. 1 is a fragmentary, isometric view of a portion of a press brake showing the position of a die and the means for changing it from one form to another.

FIG. 2 is an enlarged fragmentary cross sectional view taken along line 22 of FIG. 1.

FIG. 3 is a fragmentary sectional view taken through a portion of a press brake showing the supports for the die and the elements associated therewith.

FIG. 4 is an end View of a conventional press brake with the present invention applied thereto.

FIG. 5 is a fragmentary View of a part of the press brake of FIG. 4 as seen from line 55 of FIG. 4.

FIG. 6 is an enlarged cross sectional view taken along line 66 of FIG. 5.

In detail a press brake comprises a rigid frame generally designated 1 that includes opposed end members 2 (FIG. 4) that may be connected by stationary frame members in any suitable manner, usually below the lower die of the press as by member 3 (FIG. 2), although they may also be connected above the punch.

A horizontal elongated slide 4 extends between similar end members 2, and in the form shown in FIG. 1 the end members 2 are hollow and the ends of the slide 4 extend into vertical slots 5 formed in the inner walls 6, 7 of said end members. A vertical hydraulic cylinder 8 is within the lower end portion of each end member.

Each cylinder, in the form of the invention herein illustrated, includes a piston vertically reciprocable therein having a piston rod 9 projecting upwardly through the upper head of the cylinder, and the upper end of each rod 9 is centrally connected with a cross bar 10. Laterally projecting ears 11 are rigid with the ends of slide 4 Within each end member 2, and a pair of spaced vertical connecting rods 12 connect the ears 11 with the ends of cross bar 19. Thus upon downward movement of the piston rods 9, when the conventional hydraulic system is actuated in a normal bending or forming operation, the slide 4 will be moved downwardly, and a reversal of the usual valve in the hydraulic system will actuate the rods 9 to move the slide upwardly. Springs may return the slide in case the hydraulic cylinder is single acting. The present invention is not concerned with the particular system that is employed, although the arrangement of the hydraulic cylinders and their connections with the side, as seen in FIG. 1, is preferable and is believed to be new.

The slide 4 carries the punch 15, which punch may be held in place by set screws 16. The punch in the case of a multiple bending operation to form a channel in a sheet, may be a horizontally elongated blade having the lower edge of a cross sectional contour that corre! sponds substantially with that of the die into which the punch is movable. Many different forms may be bent by substituting a different die and punch for each different form.

By loosening the set screws 16 the punch 15 may be removed and a punch having a different cross sectional contour along its lower edge may be substituted. The shank portion 17 of punch 15 will remain the same for each form.

The die of the present invention is generally designated 19 and may be formed from a uniform diameter, horizontal, solid metal cylindrical bar 2%.

One side of the bar 29 is formed with a plurality of straight radially outwardly opening recesses 21, 22, 23, 24, more or less, each of which has a different cross sectional contour for forming bends having forms substantially corresponding to the contours of the difierent recesses.

The remaining half of the surface 26 of said bar 24) remains cylindrical in cross sectional surface contour.

The cylindrical side of said bar is adapted to be revolvably seated on a die base 27 having the same cylindrical contour as the surface 26 of the die, and this die base extends substantially from end to end of the die.

The die base may be formed directly in the cross member 3 (FIG. 2) or it may be formed in a boltser plate 28 (FIG. 6) that is adapted to be fitted on and secured to the cross frame member 3. The bolster plate 28,

1 when used, is of the type having a lower rib 30 that is adapted to seat and to be secured in the recess 31 (FIG. 6) in the conventional cross frame member of a conventional press brake, in the same manner as a separate die would be secured in place.

It is very important that the die be seated in a position below the slide 4 and punch 15 so that the lower metal bending portion of the punch that enters the uppermost recess of the recesses 21-24 will form the desired bend in sheet material extending across the die and are coaxial with the rod 20. The rod 20 and bearing.

3,fi29,858 Patented Apr. 17, 1962 members 35, 36 are connected by coaxial bars 37 (FIGS. 2, 3), which bars are eccentrically positioned relative to the longitudinal axis of the die 29, being offset to the side of said axis that is most remote from the recesses 2225. Also, the ends of the die 20 are spaced from the bearing members 35, 36. By this structure, certain metal jobs that have flanges or the like may be bent on the die by positioning the flanges or bent marginal portions of the sheet so they overhang either one end or the other of the die. The bearing members 35, 36 and bearings 32, 33 do not receive any strain from a punching operation since the die 20 is seated on its die bed, hence the bars 37 receive no strain.

By positioning the bars 37 eccentrically a relatively wide flange may overhang either end of the die without such interference from the rods as would occur were they concentric.

While the die 20, as illustrated, is adapted for use in forming four dilferent shapes, there are other bends, not shown in the die of FIG. 2. Hence several dies 29 may be required to provide the other shapes.

Bars 37 are rigid with the die 20, and the bearing members 35, 36 may be formed with recesses in which the outer ends of the bars 37 fit. The bar 37 at the right hand end of the press, as seen in FIG. 3, may be releasably held to hearing member 36 by a set screw 46.

The bearing members 35, 36 may be held in their position by collar 42, secured adjacent to the end frame member 2, which secures the bearing members in position so the die 20 will be held against longitudinal movement.

In order to replace a die 20, it is merely necessary to loosen set screws 46 and the bearing member 36 may be moved away from the die 20 to enable removal of the die. Upon replacing the die with another, the hearing member 36 is moved to receive the bar 37 adjacent thereto after the other bar 47 is in member 35, and set screw 46 is then tightened.

The bearing member 36 carries a handle 46 extending radially and generally upwardly therefrom along the outer side of the end wall 34 of the press frame. This end wall is formed with openings 47 arranged in an arc. The handle itself carries a spring urged pin 48 having a finger engageable button 49 at its outer end. The inner end of the pin is spring urged into one of the openings 47. These openings are arranged in a row, each being identified with one of the recesses 21-24 so that the recesses may be selectively held in operative relation to the punch 15. By merely pulling pin 48 outwardly and swinging the handle 46 to the desired opening, the recess identified with that opening will be uppermost and in exactly the correct position for forming the shape of that recess. By this arrangement the changing of a die shape from one to another may be accomplished in a matter of seconds.

In the press brake described, the slide 4 carrying the punch 15 is moved downwardly by its connection with the hydraulic cylinder positioned in the lower portion of the end frame members. It is not unusual to have motor driven slides, and C-type end frames, in which hydraulic cylinders are in the upper portion of the end frames. FIG. 4 shows the latter type, but whether one type or the other is used, there is usually a bolster plate that corresponds to the bolster plate 28 of FIG. 6 and which plates are adjustable, as are the slides in many instances.

In order to convert a standard press brake of the type shown in FIG. 4 it is merely necessary to provide a die base like the one shown in FIG. 6 and which die base has a rib 30 adapted to fit in the recess 31 in the bolster plate. The bearing blocks 51 (FIGS. 4, may then be provided at the ends of the die base for rotatably supporting the bearing members 35, 36. Stop openings or recesses 52 on the end frame member 53 adjacent to scene the handle 46 are provided with a pin 43, the same as in FIG. 3, for holding the die in position.

In FIG. 4, however, the recesses or openings 52 are slightly differently arranged due to there being a different end frame member than is shown in FIG. 1. However, the operation is the same.

In FIGS. 5, 6 the die, indicated generally at 54, may have the bearing members 55 at its ends directly formed on the die and coaxial therewith, instead of using the bars 37. Other modifications may be made without departing from the spirit of the main invention.

I claim:

1. In a punch press having a frame and a vertically reciprocable ram mounted thereon to which ram horizontally elongated punches of different cross sectional contours are adapted to be singly and removably secured for movement therewith, a horizontally elongated lower die below said ram, means mounting said die on said frame for rotation of said die about its longitudinal axis to different positions, said die having a radially outwardly opening recess extending longitudinally thereof for each of said different positions, each recess having a different cross sectional contour adapted to receive a punch on said ram having a similar substantially complementary cross sectional contour, one of said recesses in each of said different positions of said die being directed upwardly to receive a punch on said ram for bending metal to substantially said contour of said die, and means for releasably securing said die in each of said different positions, approximately one-half of the outer surface of said die, in cross sectional contiur, being circular and concentric with the longitudinal axis of said die, the said means mounting said die comprising an elongated, horizontally extending frame member rigid with said frame and below said die extending longitudinally of the latter, said frame member being formed with an upwardly opening recess extending longitudinally of the latter centrally formed with an upwardly opening groove, an elongated bolster removably seated within said recess having a downwardly projecting rib closely fitted within said groove, the upwardly facing surface of said bolster being circular in cross sectional contour and complementary to the contour of the said approximately one half of the outer surface of said die, and said die being rotatable on said upwardly facing surface.

2. In a punch press having a frame and a vertically reciprocable ram mounted thereon to which ram horizontally elongated punches of different cross sectional contours are adapted to be singly and removably secured for movement therewith, a horizontally elongated lower die below said ram, means mounting said die on said frame for rotation of said die about its longitudinal axis to different positions, said die having a radially outwardly opening recess extending longitudinally thereof for each of said different positions, each recess having a different cross sectional contour adapted to receive a punch on said ram having a similar substantially complementary cross sectional contour, one of said recesses in each of said different positions of said die being directed upwardly to receive a punch on said ram for bending metal to substantially said contour of said die, and means for releasably securing said die in each of said different positions, the means mounting said die for rotation including coaxial cylindrical bearing members journalled in said frame for rotation about their axes, coaxial extensions projecting from the ends of said die eccentrically positioned relative to the longitudinal axis of said die connecting said die with said bearing members and spacing said die between said bearing members, said different recesses being formed in substantially one-half of the circumferential cross sectional contour of said die that is farthest from the axis of said extensions whereby material bent by actuation of said punch and die may extend a substantial distance across the ends of said die toward said extensions free from interference therefrom.

3. A female die adapted for use in a punch press for making bends, comprising; a horizontally elongated solid cylinder adapted to be rotated about its longitudinal axis, a plurality of radially outwardly opening recesses formed in one side of said cylinder and extending from one end portion thereof to the other end thereof; said recesses having different cross sectional contours for forming different bends when said die is mounted in a punch press; an extension on said other end of said cylinder extending axially of the latter and positioned eccentrically of the longitudinal axis of said cylinder and to the side of said axis that is remote from said one side, a cylindrical hearing member coaxial with said cylinder on said extension secured thereto against rotation relative thereto and spaced from said one end to provide a space between said one end and said bearing member into which a marginal portion of a sheet adapted to extend over said recesses may be bent for forming a flange on said sheet.

4. In a construction as defined in claim 3, said bearing member being removable from said extension in a direction axially of said cylinder and away from said other end thereof to facilitate replacement of said cylinder by another having a similar extension thereon, and means for releasably securing said bearing member to said cylinder against removalthereof from said bearing member, said bearing member being elongated axially of said cylinder and including a radially extending handle thereon at the end of said member that is remote from said other end of said cylinder for rotating said cylinder when the latter is mounted on a press.

References Cited in the file of this patent UNITED STATES PATENTS 2,332,590 Mursch Oct. 26, 1943 2,456,749 Steibel Dec. 21,1948 2,510,768 Williamson June 6, 1950 FOREIGN PATENTS 440,090 Germany Aug. 1, 1888 621,291 Germany Nov. 3, 19 5 408,944 Italy Jan. 22, 1945 933,801

Germany Nov. 24, 1955 

